Mom's Stuffed Shells Florentine

I [Leeann] grew up on this recipe and wanted to share... soooo good!

1 pkg jumbo shells
1 - 10 oz pkg frozen spinach
2 lbs. ricotta cheese
1 egg
2 T parmesean cheese
1 jar marinara sauce
1/2 t salt and oregano

Bring 5 qts water to boil, add shells and parboil ~ 9 minutes. Drain and rinse in cold water immediately, draining again. Arrange on a flat surface, allowing to dry.

Cook spinach and mix with ricotta, egg and parmesean. Spoon mixture into each shell. Combine marinara with salt and oregano. Simmer about 2 minutes.
Using two 2-qt baking dishes, spread 1/2 cup sauce into each dish. Arrange shells on sauce and bake at 350 degrees for 15-20 minutes. Be careful not to allow them to cook too long, getting dried out on top.

Serve shells with remaining heated sauce.